The present invention relates to a novel method for joining ceramic parts. In one embodiment, the invention is concerned with a process for joining a lid on a containment vessel after it has been filled with nuclear or other hazardous waste.
U.S. Pat. No. 4,437,578, granted Mar. 20, 1984, discloses a method for closing with a cover a container for the final storage of radioactive substances, wherein at least one of the container and cover consists of a material selected from ceramic and metallic material, and wherein the container and cover are suitably ground on their seating areas which cooperate with each other; and when the container is closed the cover is held by prestressing on the seating area of the container. The method may include a step after grinding, of applying a thin equalizing layer of highly corrosion resistant, deformable material to at least one of the seating areas of the container and cover. The material for the layer may be a deformable ceramic.
U.S. Pat. No. 4,529,857, granted Jul. 16, 1985, discloses a method of producing a ceramic-glass-ceramic seal comprising the steps of mixing a slurry of glass sealing material and coupling agent, applying said slurry to a plurality of ceramic workpieces for sealing; surrounding said slurry and plurality of ceramic workpieces with an insulative material; microwaving said slurry and plurality of ceramic workpieces at a power, time and frequency sufficient to cause a liquid phase reaction in said slurry; and allowing said slurry and plurality of ceramic workpieces, to cool, thereby securing a ceramic-glass-ceramic seal.
U.S. Pat. No. 4,606,748, granted Aug. 19, 1986, discloses a method for producing a ceramic-glass-ceramic seal by the use of microwave energy, and a sealing mixture which comprises a glass scaling material, a coupling agent, and an oxidizer. Sodium nitrate is the most preferred oxidizer. The seal produced is said to exhibit greater strength due to its different microstructure.
U.S. Pat. No. 4,757,172, granted on Jul. 12, 1988, discloses a method for joining together two nonoxide ceramic items which involves a preliminary step of either creating a vacuum or overpressurizing a cavity, followed by the steps of applying microwave radiation to the ceramic items, simultaneously applying compressive forces to the ceramic items in order to force such ceramic items together, and continually monitoring the joint being formed between the two ceramic items. An apparatus of four basic elements carries out the method. These elements are a vacuum/overpressurization system, a single mode microwave applicator, a compressive force applicator, and a nondestructive evaluator for monitoring the formation of the joint.
U.S. Pat. No. 4,767,902, granted Aug. 30, 1988, discloses a method for joining together two ceramic items which involves the steps of applying microwave radiation to the ceramic items, simultaneously applying compressive forces to the ceramic items in order to force such ceramic items together, and continually monitoring the joint being formed between the two ceramic items. An apparatus of three elements carries out the method. These elements are a single mode microwave applicator, a compressive force applicator, and a nondestructive evaluator for monitoring the formation of the joint.
U.S. Pat. No. 4,772,770, granted Sep. 20, 1988, discloses an apparatus for joining two ceramics using microwave energy, having a cavity resonator in which the ceramics are placed; a microwave-generator means for producing microwave radiation to be introduced into the cavity resonator; a pressurizer for pressing the joining surfaces of the ceramics against each other; and a temperature controller for controlling the temperature distribution of the ceramics in such a way that the temperature of the ceramics at the joining surfaces is highest and rapidly decreases toward the unjoined ends of the ceramics. The microwave-generator may include a microwave oscillator, a klystron amplifier, and an isolator. The temperature controller can be a dielectric heater or a combination of a dielectric heater and a temperature difference-producer.
U.S. Pat. No. 4,792,348, granted Dec. 20, 1988, discloses a method of producing a joint between a beta-alumina electrolyte tube and alpha-alumina flange with a glass bonding agent in a solid annular bead form devoid of additives such as a coupling agent or the like capable of being heated when subjected to microwave energy which comprises utilizing in the heating step a source of microwave energy so as to heat the beta-alumina tube by microwave energy for a time period sufficient to enable the heat generated in the beta-alumina tube to be conducted to the glass bead and the alpha-alumina flange and heat the glass bead to a temperature above the glass deformation point, and allowing the tube to cool to solidify the glass bead in intimately penetrating relation to the surfaces of the beta-alumina tube and alpha-alumina flange engaged thereby so that the glass forms a bond between the beta-alumina tube and the alpha-alumina flange characterized by a fusion of the glass within the engaged beta-alumina and alpha-alumina.